1. Field of the Invention
The invention relates to a variable-length needle cover for an injection device.
2. Description of the Related Art
Many users of injection devices have a psychological aversion (so-called “needle phobia”) to injection needles such as those used for injecting a fluid product. Patients who actually inject the fluid product themselves often have an inhibition threshold that has to be overcome when injecting the needle. In order to reduce this inhibition threshold, needle covers have been provided for injection devices.
A variable-length needle covering device for a syringe is disclosed in WO 96/11026. The needle covering device has a porous foam material or a flexible polyethylene film. When the needle covering device is retracted, the cover is either unguided in movement or only guided by the injection needle itself. If the syringe is placed on the skin at any non-perpendicular angle to the surface of the skin, the injection needle may pierce the needle covering device.